1. Field of the Invention
The present invention relates to an information processing apparatus and, more particularly, to an information processing apparatus including a coordinates input means capable of inputting coordinates from obverse and reverse surfaces of the apparatus and a means for outputting information input from the coordinates input means.
2. Related Background Art
Conventional coordinates input apparatus using various types of input pens and tablets are known as apparatuses for inputting handwritten character and graphic information in a processor such as a computer. Image information such as input character and graphic information in the apparatus of this system is output to a display unit such as a CRT display or a recording apparatus such as a printer.
An X-Y coordinate system is set in a tablet of the apparatus of this system. Input data is input as the coordinate data. Various schemes are employed to perform coordinate detection:
(1) A scheme in which a change in resistance of a sheet member opposite to a resistance film is detected;
(2) A scheme in which an electromagnetic or electrostatic induction of a conductive sheet or the like which is arranged so as to face a coil (an inductor) is detected; and
(3) A scheme in which an ultrasonic vibration transmitted from an input pen to a tablet is detected.
An input tablet according to each scheme described above has a flat member. One conventional tablet unit has symmetrical structures on the obverse and reverse surfaces of the tablet to allow coordinate inputs on either surface.
A CAD system and a drafting system are exemplified as information processing apparatuses using the above information input/output system. In a conventional system of this type, operations on the display screen are replaced with those on drawing paper. Therefore, this system aims at simplifying editing operations such as copying, deletion, and replacement of complicated image elements.
In the above system, operations performed on the input tablet are similar to conventional operations using paper and pencils, as compared with operations using a mouse or joystick. Therefore, the user can easily perform the operations with the input tablet.
Conventional drafting with paper and pens/pencils is often performed such that the obverse and reverse sides of an object to be drawn are discriminated. Such drafting is exemplified as drafting of mechanical drawings or a graph which is drawn on tracing paper or an OHP film.
In mechanical and design drawings, hatched lines representing a sectional view and rules for filling characters and symbols are drawn on the reverse surface of paper, while shapes and dimensions are written on the obverse surface of paper. In drafting of graphs and tables, rules and a coordinate system are written on the reverse paper surface, while elements in the graph and table are written on the obverse paper surface. According to these operations, information written on the reverse paper surface is the one which need not be changed once it is written. Even if deletion, changes, and corrections are frequently repeated on the obverse paper surface, the information on the reverse paper surface is not adversely affected.
In design operations using the drawings, the coordinate system on the obverse paper surface must often be reversed when the paper is turned over because design modifications or drafting from the opposite direction of given member is required.
Even if an image is input using the input tablet described above, a strong demand has arisen for developing a processing system wherein information input on the obverse paper surface can be discriminated from that on the reverse paper surface or a coordinate system of an image input on one input surface can be reversed in accordance with use of the tablet surface in the input mode.
Even if a conventional reversible input type tablet is used, the obverse and reverse surfaces are selectively used for simply inputting information, but they cannot be discriminated from each other. Therefore, image processing based on input surfaces cannot be performed.
The above problem is not only limited to an image processing system but also is also encountered in processing of characters, symbols or coordinate information itself.